Patent Application
20210081748
The invention relates to the field of RFID-enabled metal transaction cards and, more particularly, to contactless metal cards (aka proximity metal cards), and contact and contactless metal cards (aka dual interface (DI) metal cards) having a booster antenna (BA) with an antenna structure (AS) overlying or fitting into a slit (S) in a metal card body (MCB) or a coupling loop structure (CLS) with antenna structures on a flexible circuit (FC) overlapping a module antenna (MA) and overlying or fitting into a slit (S) in a metal card body (MCB).
Some of the disclosure(s) herein may relate to an inductive coupling chip module or a flexible circuit (FC) with a sense coil (SeC) and a coupling loop structure (CLS) with an antenna structure(s) (AS), embeddable in a metal housing, casing, foldable metal structure or a laminated metal card stack-up construction.
Some of the disclosure(s) herein may also relate to Coil on Chip (CoC), Transponder Chip Module (TCM), Inductive Coupling Chip Modules (ICM) or Coil on Module (CoM) with and without contact pads. Chip modules without contact pads may be referred to as RFID chip modules or RFID flexible circuits with a Module Antenna (MA) connected to an RFID chip. RFID terminology also includes NFC or NFC/CTLS protocols.
The disclosure may relate broadly to RFID devices including electronic identification (eID) cards, employee ID cards, secure credentials, access control cards and security badges capable of operating in a “contactless” mode, meeting ISO 14443B or NFC/ISO 15693 for contactless communication.
The disclosure may further relate to identification cards which may combine 13.56 MHz contactless read/write smartcard technology and 125 kHz proximity technology on a single card with the ability to add a Wiegand strip, magnetic stripe, barcode, and anti-counterfeiting features including custom artwork or a photo identification directly on the card credential. Some of the disclosure(s) herein may relate to electronic identification cards and financial payment cards having a contact and a contactless interface.
The techniques disclosed herein may also be applicable to RFID devices including “non-secure smartcards and tags” such as contactless cards in the form of identification tags worn by military personnel, medic-alert tags, loyalty cards, asset tags, event passes, hotel keycards, small form factor tags, key-fobs, data carriers and the like operating in close proximity with a contactless reader.
Passive radio frequency identification (RFID) cards come in two form factors: clamshell cards and ISO compliant laminated cards similar to financial payment cards. The cards may have a slot punched for attachment to a lanyard or keychain via a standard clip aperture. The cards may be programmed and printed with custom artwork.
In recent times, the operating frequency of proximity cards has shifted from 125 kHz to 13.56 MHz read/write contactless technology providing high-speed, reliable communication with high data integrity.
13.56 MHz read/write contactless smartcard technology can be used for diverse applications such as access control, time and attendance, network log-on security, biometric verification, cashless vending, public transportation, airline ticketing and customer loyalty programs.
Clamshell cards or badges are among the most popular contactless identification card form factor in access control or time and attendance applications in corporate, government and educational environments.
Clamshell cards have the following features:
The ISO 7810 compliant cards are laminated PVC cards that may be printed on both sides, using most standard direct-image and thermal transfer card printers. The ISO model may support vertical or horizontal slot punching. A magnetic stripe with high coercivity (4,000 Oersted—unencoded) may provide an added swipe card capability.
ISO cards have the following features:
U.S. Pat. No. 6,214,155 (2001 Apr. 10; Leighton) discloses a radio frequency identification card and hot lamination process for the manufacture of radio frequency identification cards. A plastic card, such as a radio frequency identification card, including at least one electronic element embedded therein and a hot lamination process for the manufacture of radio frequency identification cards and other plastic cards including a micro-chip embedded therein. The process results in a card having an overall thickness in the range of 0.028 inches to 0.032 inches with a surface suitable for receiving dye sublimation printing. The variation in card thickness across the surface is less than 0.0005 inches. A card manufactured also complies with all industry standards and specifications. Also, the hot lamination process results in an aesthetically pleasing card.
A dual interface (DI or DIF) smartcard (or smart card (SC)), as an example of an RFID device, may generally comprise:
The transponder chip module (TCM), which may be referred to as an inductive coupling chip module (ICM), or RFID module may generally comprise:
The module antenna (MA) of the transponder chip module (TCM) may couple with an in-card booster antenna (BA) or coupling frame (CF).
The module antenna (MA) may be a planar antenna (PA) which is etched from a foil (which may be supported by the module tape (MT, CCT) to have a spiral track having a number of turns. The track (hence turns) may measure approximately 70 μm in width. Spaces between adjacent turns of the spiral track may measure approximately 75 μm (chemical etching) or 25 μm (laser etching) in width. Etching may be performed by chemical means, or laser ablation, or a combination thereof.
When operating in a contactless mode, a passive transponder chip module (TCM) may be powered by RF from an external RFID reader and may also communicate by RF with the external RFID reader.
In the main, hereinafter, RFID devices such as proximity cards, dual interface smartcards, and objects incorporating a transponder chip module may be passive devices, not having a battery and harvesting power from an external contactless reader (ISO 14443). However, some of the teachings presented herein may find applicability with cards having self-contained power sources, such as small batteries or supercapacitors.
In addition, some of the teachings presented herein may be applicable to UHF proximity cards made of metal.
US 2020/0034578 (2020 Jan. 30; Finn et al.) discloses SMARTCARD WITH DISPLAY AND ENERGY HARVESTING. A wireless connection may be established between two electronic modules (M1, M2) disposed in module openings (MO-1, MO-2) of a smartcard so that the two modules may communicate (signals, data) with each other. The connection may be implemented by a booster antenna (BA) having two coupler coils (CC-1, CC-2) disposed close to the two modules, and connected with one another. The booster antenna may also harvest energy from an external device such as a card reader, POS terminal, or a smartphone. A coupling antenna (CPA) may have only the two coupler coils connected with one another, without the peripheral card antenna (CA) component of a conventional booster antenna. A module may be disposed in only one of the two module openings. As disclosed therein:
The following US patents and patent application publications are referenced, some of which may relate to “RFID Slit Technology”:
Some Additional US Patents and Publications
Some of the following terms may be used or referred to, herein. Some may relate to background or general knowledge, others may relate to the invention(s) disclosed herein.
Eddy currents are induced electrical currents that flow in a circular path. In other words, they are closed loops of induced current circulating in planes perpendicular to the magnetic flux. Eddy currents concentrate near the surface adjacent to the excitation coil of the contactless reader generating the electromagnetic field, and their strength decreases with distance from the transmitter coil. Eddy current density decreases exponentially with depth. This phenomenon is known as the skin effect. The depth that eddy currents penetrate into a metal object is affected by the frequency of the excitation current and the electrical conductivity and magnetic permeability of the metal.
Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor, and decreases with greater depths in the conductor. The electric current flows mainly at the “skin” of the conductor, between the outer surface and a level called the skin depth. The skin effect causes the effective resistance of the conductor to increase at higher frequencies where the skin depth is smaller, thus reducing the effective cross-section of the conductor. The skin effect is due to opposing eddy currents induced by the changing magnetic field resulting from the alternating current.
A discontinuity interrupts or alters the amplitude and pattern of the eddy currents which result from the induced electromagnetic field generated by a contactless point of sale terminal. The eddy current density is highest near the surface of the metal layer (ML) and decreases exponentially with depth.
Providing a metal layer in a stack-up of a card body, or an entire metal card body, to have a module opening for receiving a transponder chip module (TCM) and a slit (S) to improve contactless (RF) interface with the card—in other words, a “coupling frame”—may be described in greater detail in U.S. Pat. Nos. 9,475,086, 9,798,968, and in some other patents that may be mentioned herein. In some cases, a coupling frame may be formed from a metal layer or metal card body having a slit, without having a module opening. A typical slit may have a width of approximately 100 μm. As may be used herein, a “micro-slit” refers to a slit having a smaller width, such as approximately 50 μm, or less.
“RFID Slit Technology” refers to modifying a metal layer (ML) or a metal card body (MCB) into a so-called “antenna circuit” by providing a discontinuity in the form of a slit, slot or gap in the metal layer (ML) or metal card body (MCB) which extends from a peripheral edge to an inner area or opening of the layer or card body. The concentration of surface current at the inner area or opening can be picked up by another antenna (such as a module antenna) or antenna circuit by means of inductive coupling which can drive an electronic circuit such as an RFID chip attached directly or indirectly thereto. The slit may be ultra-fine (typically less than 50 μm or less than 100 μm), cut entirely through the metal with a UV laser, with the debris from the plume removed by ultrasonic or plasma cleaning. Without a cleaning step after lasing, the contamination may lead to shorting across the slit. In addition, the slit may be filled with a dielectric to avoid such shorting during flexing of the metal forming the transaction card. The laser-cut slit may be further reinforced with the same filler such as a resin, epoxy, mold material, repair liquid or sealant applied and allowed to cure to a hardened state or flexible state. The filler may be dispensed or injection molded. The term “slit technology” may also refer to a “coupling frame” with the aforementioned slit, or to a smartcard embodying the slit technology or having a coupling frame incorporated therein.
The term “module antenna” (MA) may refer to an antenna structure (AS) located on the face-down-side of a transponder chip module (TCM) or dual interface chip module (DI chip module) for inductive coupling with an in-card booster antenna (BA) or coupling frame (CF). The antenna structure (AS) is usually rectangular in shape with dimensions confined to the size of the module package having 6 or 8 contact pads on the face-up-side. The termination ends of the antenna structure (AS) with multiple windings (13 to 15 turns) based on a frequency of interest (e.g. 13.56 MHz) are bonded to the connection pads (LA and LB) on the RFID chip. In the case of a coupling frame (CF) smartcard such as a dual interface metal core transaction card, the module antenna (MA) overlaps the coupling frame (CF) or metal layer(s) within the card body at the area of the module opening to accept the transponder chip module (TCM).
The term “coupling loop antenna” (CLA) may refer to an antenna structure (AS) which couples to a module antenna (MA) in a transponder chip module (TCM). The windings or traces of the coupling loop antenna (CLA) may intertwine those windings of the module antenna (MA), or the windings or traces of the coupling loop antenna (CLA) may couple closely with the windings of the module antenna (MA) similar in function to a primary and secondary coil of a transformer. The termination ends of a coupling loop antenna (CLA) may be connected to termination points (TPs) across a discontinuity in a metal layer (ML) or metal card body (MCB) acting as a coupling frame (CF).
The term “coupling frame antenna” (CFA) may refer to a metal layer or metal card body with a discontinuity may be represented by card size planar antenna having a single turn, with the width of the antenna track significantly greater than the skin depth at the frequency of interest.
The terms “Sense Coil” (SeC), “Patch Antenna” (PA) and “Pick-up Coil” (PuC) may refer to various types of coils or antennas used to capture surface current by means of inductive coupling at the edge of a metal layer (ML) or metal card body (MCB) or around a discontinuity in a metal layer (ML) or metal card body (MCB) when such conductive surfaces are exposed to an electromagnetic field. The coils or antennas may be wire wound, chemically etched or laser etched, and positioned at very close proximity to a discontinuity in a metal layer, at the interface between a conductive and non-conductive surface, or at the edge of a metal layer.
The term “antenna cell” (AC) may refer to an antenna structure (AS) such as sense coil (SeC), patch antenna (PA) or pick-up coil (PuC) on a flexible circuit (FC) driving an electronic component such as a fingerprint sensor or a dynamic display. A plurality of antenna cells (ACs) at different locations in a metal transaction card may be used to power several electronic components.
A pick-up antenna in the form of a micro-metal strip (first electrode) may be placed in the middle of a discontinuity to probe eddy current signals from the magnetic flux interaction with the metal layer acting as the coupling frame. The metal layer also acts as the second electrode in the circuit. The metal strip may be replaced by a sense coil with a very fine antenna structure to pick-up the surface currents from within the discontinuity.
A booster antenna (BA) in a smartcard comprises a card antenna (CA) component with multiple turns or windings extending around the periphery edge of the card body (CB), a coupler coil (CC) component at a location for a module antenna (MA) of a transponder chip module (TCM), and an extension antenna (EA) component contributing to the inductance and tuning of the booster antenna (BA). A conventional booster antenna is a wire embedded antenna, ultrasonically scribed into a synthetic layer forming part of the stack-up construction of a dual interface smartcard. The card antenna (CA) on the periphery of the card body (CB) inductively couples with the contactless reader while the coupler coil (CC) inductively couples with the module antenna (MA) driving the RFID chip.
U.S. Pat. No. 9,033,250 (2015 May 19; Finn et al.) discloses a booster antenna (BA) for a smart card comprises a card antenna (CA) component extending around a periphery of a card body (CB), a coupler coil (CC) component at a location for an antenna module (AM), and an extension antenna (EA) contributing to the inductance of the booster antenna (BA).
The term “coupling loop structure” may refer to a flexible circuit (FC) with a sense Coil (SeC), patch antenna (PA) or pick-up coil (PuC) for inductive coupling with a discontinuity in a metal layer (coupling frame) to pick-up surface currents and to direct such currents via traces or tracks to an antenna having a frame or spiral shape on the flexible circuit (FC) which further inductively couples in close proximity with the module antenna (MA) of a transponder chip module (TCM).
For optimum RF performance, the dimensional width of the windings (or width across multiple windings) of a sense coil (SeC), patch antenna (PA) or a pick-up coil (PuC) ought to overlap a metal edge (ME) of a slit, gap or notch in the card body by 50% of the distance across the windings to capture the surface currents at the metal edge (or ledge).
A sense coil (SeC), patch antenna (PA) or a pick-up coil (PuC) (all or which may be referred to as “antennas”, or antenna structures (AS)) may comprise multiple windings (or tracks), and may have a width. For optimum performance, the antenna should overlap a metal edge (ME).
The same principle of overlap may apply to the module antenna (MA) of a transponder chip module (TCM) implanted in a metal containing transaction card. The dimensional width of the windings of the module antenna (MA) ought to overlap a metal ledge (P1) of a stepped cavity forming the module pocket in a card body by 50% of the distance across the windings of the module antenna (MA).
In the case of an antenna structure (AS) which is an antenna probe (AP), which does not overlap a slit or gap, but rather is disposed within the slit or gap, surface currents may be collected when the antenna probe (AP) is between and very close to the metal edges forming the slit or gap. The probe is disposed within the slit, and dimensional fits into the slit being at close proximity to the walls of the slit. As the shape and form of the antennas may change, the dimensional width of the windings may be replaced by the surface area or volume.
It is an object of the invention(s), as may be disclosed in various embodiments presented herein, to provide improvements in the manufacturing, performance and/or appearance of smartcards (also known as transaction cards), such as metal transaction cards and, more particularly, to RFID-enabled smartcards (which may be referred to herein simply as “cards”) having at least contactless capability, including dual interface (contactless and contact) smartcards, including cards having a metal layer in the stackup of their card body, and including cards having a card body which is substantially entirely formed of metal (i.e., a metal card body).
The invention(s) disclosed herein make use of the surface eddy currents which flow along the perimeter edge of a conductive surface such as a metal card body (MCB) which has been exposed to electromagnetic waves, generated by a contactless reader or terminal. The intensity of such eddy currents at the frequency of interest is a maximum along the skin depth of the metal at its perimeter edge. The skin depth of copper, for example, at 13.56 MHz is approximately 18 μm.
The distance in which the slit (S) or notch (N) needs to extend from the perimeter edge across the metal layer (ML) or metal card body (MCB), concentrating the surface current density, needs to be a substantial multiple of the skin depth distance to facilitate the diversion of current. Notably, the slit (S) or notch (N) passes entirely through the metal layer (ML, MCB), and the shape of the slit or notch can be straight, curved, u-shaped or have any arbitrary form. The slit (S) or notch (N) may terminate in an opening (MO) which may be rectangular in shape, or other than rectangular in shape.
In order to divert the surface currents from the surrounding area of a slit (S) or notch (N) and an opening to an area destined for the implanting of a transponder chip module (TCM) with a module antenna (MA) connected to an RFID chip, a flexible circuit (FC) may be used for inductive coupling and harvesting energy. Such flexible circuit (FC) may have a patch antenna (PA) (aka a sense coil (SeC)) to pick-up the surface currents around the area of the slit (S) or notch (N) and opening, conduct such current flows to a coupling loop structure (CLS) having a frame, circular, spiral or helix shape antenna structure (AS) on the flexible circuit (FC) which collects and distributes current flows and inductively couples with the module antenna (MA) of the transponder chip module (TCM) by means of the patch antenna (PA). The flexible circuit (FC) may be replaced by a rigid circuit (RC). For the purpose of clarity, a transponder chip module (with contact pads) may be replaced or interchanged by an RFID chip module (having no contact pads) for application in high (HF) and ultra-high frequency (UHF) proximity cards and contactless payment cards.
According to the invention, generally, proximity cards or contactless smartcards can be manufactured from folding a metal layer to form a metal card body (MCB) having the dimensions of a standard ID-1 smartcard comprising (i) a slit in the metal layer which extends from a perimeter edge to a shaped opening or window and (ii) folding the metal layer in the middle on one fold line to form a sandwich having a separation gap at the edge of the card body, or folding the metal layer on two fold lines forming wings which are folded back onto the card body with a separation gap between the two wings in the center of the card body, and after folding and pressing the metal layers together forming a proximity card having ID-1 dimensions which is ISO compliant; and (iii) said ID-1 proximity card having an antenna structure (AS) on a flexible or rigid circuit sandwiched powering an RFID chip between the folded metal layer or metal layers to overlap or overlie the slit or slits, opening or openings, and the isolation gap between the folded metal layer on layers forming the metal card body (MCB).
According to the invention, generally, a contactless metal face/metal hybrid smartcard has a booster antenna (BA) arranged on a rear plastic layer laminated to a front metal layer having a slit (S). The booster antenna may have three portions, or components: (i) a perimeter coil (PC) component extending around a peripheral area of the card body, and having one or more turns; (ii) a coupling or coupler coil (CC) component located at the module opening (MO) for coupling with a module antenna (MA) in the transponder chip module (TCM), and having one or more turns; and (iii) a sense coil (SeC) component arranged around the slit (S) in the front metal layer, and may overlap the slit (S), typically in a zigzag fashion or the like. The sense coil may have a loop, spiral or helix shape. The booster antenna may form a closed loop circuit, and may have no free ends. Alternatively, the booster antenna may form an open loop circuit, and may have free ends.
The invention may be applicable to contactless-capable cards such as proximity cards (PC), and smartcards (SC) having metal layers (ML) with slits (S) to function as coupling frames (CF). Some of the descriptions directed to ID-1 size smartcards may be applicable to proximity cards, and vice-versa. The smartcards (SC) may be contactless only, or may be dual interface (DI) having both contactless and contact capability. Contactless capability relies on establishing a radio frequency (RF) connection between the card and an external contactless reader, such as a point-of-sale (POS) terminal. Contact capability is relatively straightforward, involving having contact pads (CP) on an exposed face of the transponder chip module (TCM), for interfacing with an external contact type reader, such as an automatic teller machine (ATM).
According to some embodiments (examples) of the invention, a method of making a card body (CB) for an RFID device of a given size may comprise: providing an oversize metal layer (OML) having a full size middle portion (MP) flanked by two half size side portions (SP) extending from opposite side edges of the middle portion; folding the two side portions, towards each other, over the middle portion so that their outer edges (oe) oppose and nearly touch each other, leaving a slit (S) therebetween. An insulating layer may be provided between the middle portion and the side portions. A full size module opening (fMO) may be provided in the middle portion; and a half size module opening (hMO) may be provided in each of the side portions. The side portions may be folded over the middle portion so that the half size module openings oppose each other, and together form a full size module opening. A slit (S) may be provided in the middle portion. After folding, one (or both) of the outer edges may be trimmed. An antenna structure may be provided which is adjacent to or overlaps the slit. The RFID device may be a smartcard (SC) or a proximity card (PC).
The middle portion may represent a first metal layer (ML-1); the folded over side portions may represent a second metal layer (ML-2). An RFID chip module may be provided between the two metal layers. Both metal layers may be provided with a slot to accept a lanyard.
According to some embodiments (examples) of the invention, a smartcard may comprise: a coupling frame (CF) comprising a metal layer (ML) with a slit (S); and a booster antenna (BA). The booster antenna may comprise a sense coil (SeC) disposed in, or across, or overlapping the slit, including an area adjacent to the slit. Ferrite may be disposed between the booster antenna and the coupling frame. The smartcard may be a contactless smartcard, or a dual interface (contactless and contact) smartcard.
The booster antenna may comprise: a perimeter coil (PC) component extending around a peripheral area of the card body, and having one or more turns; a coupling or coupler coil (CC) component located at the module opening for coupling with an antenna (MA) in the transponder chip module, and having one or more turns; and a sense coil (SeC) component located at an area of the slit. The sense coil may have a zigzag, loop, helical or spiral shape. The sense coil may cross over the slit several times, perpendicular to and overlapping the slit. The sense coil may traverse back and forth (meander) in the slit, parallel to the slit. The sense coil may act like a pickup coil) interacting/coupling with the coupling frame, at the location of the slit, and may comprise one or more of the following:
The booster antenna may comprise wire embedded in a plastic layer (PL). Ferrite may be disposed between the plastic layer and the coupling frame. The ferrite may be disposed only on an area on the plastic layer which is within (interior) to the booster antenna and which is not occupied by the booster antenna.
The booster antenna may form a closed loop, with no free ends. The booster antenna may form an open loop circuit, with free ends
The smartcard may further comprise a transponder chip module (TCM) capable of functioning in at least a contactless mode. The transponder chip module may have contact pads for functioning in a contact mode.
In an embodiment of the invention, the flexible circuit (FC) with a patch antenna (PA) or sense coil (SeC) to pick-up the surface currents around the area of a slit (S) or notch(es) (N) and an opening may be connected directly to the RFID chip without the need for a module antenna. In other words, the connection pads or terminal ends on the RFID chip are physically connected to the coupling loop structure (CLS) with an antenna structure (AS).
A Coil on Chip (CoC) device may also find application in HF and UHF proximity cards.
In an embodiment of the invention, a contactless metal clamshell card, metal layered card or solid metal card adhering to the physical dimensions of ISO/IEC 7810 ID-1 format to serve as a proximity card (or “prox” card) in the application of identification, access control or payment may be prepared with a slot or aperture punched or laser-cut through the metal layer or layers. The slot through the metal layer(s) of the ISO card body format may have the dual purpose of allowing for electromagnetic reception and transmission to and from an embedded RFID chip module (without contact pads) or Coil on Chip (CoC) device interfacing with a coupling loop structure (CLS) sandwiched between the metal layers, and for attachment to a lanyard. The metal layers may have a slit which starts at a perimeter edge of the metal card body and terminates in the lanyard slot.
The lanyard slot or opening in the metal layer or layers may be prepared with an insulating insert or snap mechanism made of plastic, glass or wood to allow for an enlargement of the opening in the metal layer or layers, and or to protect any circuitry exposed in the opening area.
An RFID chip module with a module antenna (MA), a flexible circuit (FC) with patch antenna (PA) and a coupling structure (CLS) with an antenna structure (AS), or a flexible circuit (FC) with an antenna structure (AS) connected to an RFID chip may reside under said insulating medium and simultaneously be adjacent, overlapping or overlying the metal layer or layers, slit and opening.
A slit (S) passing entirely through a metal layer or layers may extend from a perimeter edge of the metal card body (MCB) to a distance close to the lanyard slot or terminate in the lanyard slot.
A single metal layer may be folded on itself to form the metal card body (MCB) in ID-1 format. The metal layer or layers (ML) may be stamped and prepared with perforations for bending at one edge or two edges to form the metal card body (MCB). The metal layer or layers (ML) may have indents or pouches to accept an electronic component such as an RFID chip module. In addition, the metal layer or layers (ML) may have a slit (S) and when folded, the slit follows the direction of the fold at the edge of the metal card body. Ferrite may be used for shielding or for forming an inductive barrier between metal layers having current flows of opposite direction. The slit (s) along the edge of a metal card body (MCB) may terminate in an opening or window which may have a particular form and shape.
The metal layers of the card body may be hermetically sealed using an adhesive or the metal layers may be riveted together. The metal layers may be joined together using a ratchet mechanism or the metal layers may be welded together. In particular the metal layers may be joined together at one edge of the metal card body to avoid folding of a single metal layer.
The metal layers may be a combination of different metals such as titanium, stainless steel or an alloy, layered together, to regulate the weight of the proximity card. The metal layers of different material may be fused together to produce a composite structure.
The metal layers may be separated and fused together by a non-conducting oxide layer, a ceramic layer or a dielectric layer.
In another embodiment of the current invention, the joining and the electrical connection of the metal layers by means of spot welding or riveting may be used to direct the surface currents along the perimeter edges and within the metal card body (MCB). Such electrical connection points between metal layers to divert the surface currents to concentrate around an RFID chip module may be achieved with one or multiple connection points.
In an embodiment of the invention, a slit in a metal layer or layers is replaced by the separation distance or gap between the metal layers. An RFID chip module may be embedded between said metal layers with the concentration density of current being manipulated by the electrical connection point(s) between the metal layers.
In an embodiment of the invention, an RFID chip module or a flexible circuit with an antenna structure (AS) connected to an RFID chip is assembled between the metal layers adjacent, overlapping, overlying or surrounding the aforementioned electrical connection point(s). The RFID chip module (CM) or flexible circuit (FC) with an antenna structure (AS) connected to an RFID chip (IC) may further be disposed in an opening or window. The antenna structure on the flexible circuit (FC) may have a frame, circular, spiral or helix shape antenna formed around said opening or window to pick-up surface currents at or around the electrical connection point(s) between the metal layers. The physical joining of the metal layers to create an electrical connection point between the metal layers may be performed by means of laser welding, riveting or soldering. A recess or pouch in a metal layer or in both metal layers may be formed to house the RFID chip module or flexible circuit. The metal card body may be disposed with a slot to accept a lanyard while at the same time the aperture in the metal card body enhances the RF performance of the RFID chip module assembled adjacent or overlapping or overlying said slot or aperture. The slot or aperture passing through the entirety of the metal card body may be further disposed with a slit extending inward to an area around the electrical connection point(s). The RFID chip module (CM) disposed with a module antenna (MA) having a spiral, circular, frame or helix shape antenna may be assembled to be adjacent or overlapping or overlying the inward extending slit and/or slot. A variation in the construction of the proximity card or contactless smartcard may support a slit extending from a perimeter edge on each metal layer to the lanyard slot to further enhance RF performance.
In an embodiment of the invention, the slit may have a typographic form such as the contour of a signature. The sides of the proximity card may have indents or notches for handling.
In an embodiment of the invention, proximity cards or contactless smartcards may comprise a metal layer initially having approximately twice the dimensional size of a standard ID-1 smartcard having a slit in the middle of the oversized metal layer which extends from a perimeter edge to a shaped opening or window in the metal. By folding the metal layer lengthwise on two fold lines which are separated by a distance equal to the width of a single ID-1 card, the folded metal wings, for example with a dimensional width of half an ID-1 card, can be bent and pressed inwards to form a proximity card having ID-1 dimensions which is ISO compliant. After folding the metal wings inwards, the card body is planar with a nominal thickness of 0.76 mm Each folded metal wing can be straight or have a defined shape, and the dimensions of each wing can be the same or different, but when the wings are folded inwards and pressed flat they precisely meet, for example in the center, leaving just an isolation gap between the folded wings.
Folding the oversized metal layer on two fold lines is exemplary of the disclosure, and a proximity card in ID-1 format could equally be formed from an oversized metal layer based on one fold line. The folded wings are separated by an isolation gap in the middle of the card body, but equally the isolation gap could be at the edge of the card body, if one fold had been chosen. An adhesive layer may be applied to the card construction to fix the folded metal wings in place.
The ID-1 proximity card may further comprise of an antenna structure (AS) on a flexible or rigid substrate (circuit) assembled between the folded metal wings around the area of the lower and upper openings with slit. In other words, the flexible or rigid substrate with an antenna structure (AS) is sandwiched between the folded metal wings separated by a small gap, and the substrate is mounted around the area of openings and or slits. The antenna structure (AS) or tracks may be routed on both sides of the flexible or rigid circuit (double sided antenna structure) with its end portions connected directly to an RFID chip or via inductive coupling to an RFID chip module having a module antenna.
Other electrical components/elements such as a sensor or light may be integrated into the antenna structure (AS), and the antenna structure (AS) may be protected by a transparent, translucent or opaque material assembled around the area of the openings.
The geometry of the antenna structure (AS) may resemble a flat helix antenna design. The metal layers may be electrically connected to the doubled sided antenna structure. For the purpose of clarity, the folding of the oversized metal layer may be at any of the four sides which form the metal card body (MCB), the slit or slits may commence at any perimeter edge of the four sides, and the opening or openings in the metal layer (ML) to which the slit or slits transcend may commence at a card body edge and extend to a front face or an rear face of the metal card body (MCB). In the teachings set out above and below, the folded oversized metal layer to form two metal layers to capture surface currents is exemplary and not limited to the scope of the invention. Further, the helix antenna module is also exemplary of an antenna structure to pick-up surface currents.
According to an embodiment of the invention, contactless cards operating in contactless mode including dual interface (contact and contactless) smartcards may have a coupling frame (CF) and a booster antenna (BA) arranged in a metal card body (MCB) to inductively interact in an electromagnetic field, allowing for enhanced radio frequency performance. The metal card body may have a front face metal layer (ML) and a rear plastic layer (PL) with contactless communication possible from both sides of the card body. The booster antenna (BA) may comprise of a coupler coil (CC), perimeter coil (PC) (aka card antenna (CA)), a sense coil (SeC) and in some circumstances an extension antenna (EA) which collectively harvest and distribute energy with the front face metal layer (ML) having at least one slit (S) to act as a coupling frame (CF). The slit (S) may be a narrow gap or notch in the metal layer (ML) or the slit (S) may be an enlarged gap in the form of an opening in the metal layer (ML) or the slit (S) may be a narrow gap accompanied by an opening in the metal layer (ML). The sense coil (SeC) forming part of the perimeter coil (PC) of the booster antenna (BA) may have a single turn or multiple turns in the shape of a loop, spiral or zigzag antenna which overlaps or overlies a slit and or opening in the metal layer (ML). The perimeter coil (PC) may have a single turn or multiple turns (windings) running along the outer edges of the card body and the coupler coil (CC) may have a single turn or multiple turns to inductively couple with the module antenna (MA) of the transponder chip module (TCM). For optimum pick-up and distribution of surface currents, opposing slits and or openings may be formed in the metal card body (MCB).
In their various embodiments, the invention(s) described herein may relate to industrial and commercial industries, such RFID applications, proximity cards, contactless payment smartcards (metal, plastic or a combination thereof), electronic credentials, identity cards, loyalty cards, access control cards, wearable devices, and the like.
Other objects, features and advantages of the invention(s) disclosed herein may become apparent in light of the following illustrations and descriptions thereof.
Reference will be made in detail to embodiments of the disclosure, non-limiting examples of which may be illustrated in the accompanying drawing figures (FIGs). The figures may generally be in the form of diagrams. Some elements in the figures may be stylized, simplified or exaggerated, others may be omitted, for illustrative clarity.
Although the invention is generally described in the context of various exemplary embodiments, it should be understood that it is not intended to limit the invention to these particular embodiments, and individual features of various embodiments may be combined with one another. Any text (legends, notes, reference numerals and the like) appearing on the drawings are incorporated by reference herein.
Some elements may be referred to with letters (“AS”, “CBR”, “CF”, “CLS”, “FC”, “MA”, “MT”, “TCM”, etc.) rather than or in addition to numerals. Some similar (including substantially identical) elements in various embodiments may be similarly numbered, with a given numeral such as “310”, followed by different letters such as “A”, “B”, “C”, etc. (resulting in “310A”, “310B”, “310C”), and may collectively (all of them at once) referred to simply by the numeral (“310”).
Various embodiments (or examples) may be described to illustrate teachings of the invention(s), and should be construed as illustrative rather than limiting. It should be understood that it is not intended to limit the invention(s) to these particular embodiments. It should be understood that some individual features of various embodiments may be combined in different ways than shown, with one another. Reference herein to “one embodiment”, “an embodiment”, or similar formulations, may mean that a particular feature, structure, operation, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Some embodiments may not be explicitly designated as such (“an embodiment”).
The embodiments and aspects thereof may be described and illustrated in conjunction with systems, devices and methods which are meant to be exemplary and illustrative, not limiting in scope. Specific configurations and details may be set forth in order to provide an understanding of the invention(s). However, it should be apparent to one skilled in the art that the invention(s) may be practiced without some of the specific details being presented herein.
Furthermore, some well-known steps or components may be described only generally, or even omitted, for the sake of illustrative clarity. Elements referred to in the singular (e.g., “a widget”) may be interpreted to include the possibility of plural instances of the element (e.g., “at least one widget”), unless explicitly otherwise stated (e.g., “one and only one widget”).
In the following descriptions, some specific details may be set forth in order to provide an understanding of the invention(s) disclosed herein. It should be apparent to those skilled in the art that these invention(s) may be practiced without these specific details. Any dimensions and materials or processes set forth herein should be considered to be approximate and exemplary, unless otherwise indicated. Headings (typically underlined) may be provided as an aid to the reader, and should not be construed as limiting.
Reference may be made to disclosures of prior patents, publications and applications. Some text and drawings from those sources may be presented herein, but may be modified, edited or commented to blend more smoothly with the disclosure of the present application.
In the main hereinafter, RFID cards, proximity cards, contactless cards, dual interface cards, or tags in the form of pure contactless cards, access control cards, electronic identity cards and secure credential cards may be discussed as exemplary of various features and embodiments of the invention(s) disclosed herein. As will be evident, many features and embodiments may be applicable to (readily incorporated in) other forms of smartcards, such as dual interface cards, EMV payment cards, solid metal cards, metal veneer cards, metal hybrid cards and metal foil cards. As used herein, any one of the terms “transponder”, “tag”, “smartcard”, “data carrier” and the like, may be interpreted to refer to any other of the devices similar thereto which operate under ISO 14443 or similar RFID standard. The following standards are incorporated in their entirety by reference herein:
A typical RFID chip module (CM) (without contact pads) described herein may comprise:
Generally, any dimensions set forth herein are approximate, and materials set forth herein are intended to be exemplary. Conventional abbreviations such as “cm” for centimeter”, “mm” for millimeter, “μm” for micron, and “nm” for nanometer may be used.
According to the Prior Art, a coupling frame (CF) may generally comprise a conductive, planar surface or element (such as a conductive layer, or a conductive foil) having an outer edge, and discontinuity such as a slit (S) or a non-conductive stripe (NCS) extending from the outer edge of the conductive surface to an interior position thereof. The coupling frame may be a curved surface, rather than being planar.
Most of the coupling frames may have a “continuous” surface, and may comprise a foil or sheet or layer of metal having a slit (an electrical discontinuity) for overlapping a module antenna and, in some cases having an appropriate opening (MO) for accommodating the mounting of a transponder chip module (TCM).
In use, a coupling frame may be disposed closely adjacent to (in close proximity, or juxtaposed with) a transponder chip module (TCM) having a module antenna (MA) so that the slit (S) overlaps (traverses, over or under) at least a portion of the module antenna. For example, the slit (S) may extend from a position external to the module antenna (MA), crossing over (or overlapping) at least some of the traces of the module antenna, such as extending over all of the traces on one side of the module antenna and may further extend into the interior area (no-man's land) of the module antenna.
In dual interface metal cards according to the prior art, a stack of metal layers each with a slit at different orientations is laminated together to form a metal card body, acting as a coupling frame.
In the current invention, a slit on the same plane as the metal layer may not be a requirement.
But rather the slit is replaced by a gap between the metal layers with an electrical interconnection being provided between said metal layers at a point or position close to the perimeter edge of the metal card body formed by the metal layer sandwich. The gap may be created by a dielectric medium such as an adhesive layer or insulating layer such as a ceramic layer or by means of a non-conductive oxide. The RFID chip module (with module antenna connected to an RFID chip, a coupling loop structure (CLS) with an antenna structure (AS) and in some instances a capacitor, all mounted on the flexible substrate or circuit resides between the metal layers. The coupling loop structure (CLS) may be on a regular dielectric (e.g. polyimide film, PET, PEN, etc.) or on an electromagnetic shielding material for high frequency or ultra-high frequency RFID systems.
The electrical connection point concentrates the surface currents. The component elements of the flexible substrate or circuit are arranged in such a manner to tap into the surface currents to drive the RFID chip. In addition, a slit may be provided in the metal card body to facilitate electromagnetic reception and transmission.
The first coupling frame (CF-1) surrounds the top, left and bottom edges of the transponder chip module (TCM) 210, and extends to the top, left and bottom edges of the card body (CB), and has a module opening (MO-1). The second coupling frame (CF-2) surrounds the top, right and bottom edges of the transponder chip module (TCM), and extends to the top, right and bottom edges of the card, and has a module opening (MO-2). In aggregate, the first and second coupling frames (which may be referred to as “220”) cover nearly the entire surface of the card body 202 (less the area of the transponder chip module TCM). An activation distance of 40 mm was achieved.
The end portions of one coupling frame may be connected with the end portions of another coupling frame, in various combinations. For example, in the case of two connected coupling frames the connection may be represented as shown in
The connection may be any form of electrical connection including soldered wire, plated through hole, wire bond, conductive adhesive, crimp, ribbon wire, etc. The use of different connection configurations may yield different resonant frequency values when the “composite” coupling frame (2 or more connected coupling frames) is paired with a suitable TCM. The use of multiple coupling frames can be used to increase communication performance of the device by tuning and/or by increasing the effective size of the coupling frame by electrically linking individual coupling frames that are spatially separated. This may be particularly relevant in the case of payment objects such as payment bracelets.
In
The techniques disclosed herein may be applicable to coupling frames having slits, without module openings, and disposed so that the slit of a coupling frame overlaps at least a portion (such as one side of) a module antenna (such as a rectangular spiral planar etched antenna structure).
Proximity Card or Contactless Smartcard with Integrated Coupling Frame
Proximity cards, contactless smartcards or dual interface smartcards having (i) two metal layers (without a slit extending to a perimeter edge) forming an ISO compliant metal card body, separated by an isolation gap or a dielectric and electrically connected at one or multiple positions/points close to the perimeter edge of the metal card body to act as a coupling frame; (ii) an RFID chip module with a module antenna or a flexible circuit with an antenna structure (AS) connected to an RFID chip is assembled between the metal layers adjacent, overlapping, overlying or surrounding the electrical connection point(s); (iii) the RFID chip module or flexible circuit with an antenna structure (AS) connected to an RFID chip may further be disposed in an opening or window. The antenna structure (AS) may have a frame, circular, spiral or helix shape formed around said opening or window to pick-up surface currents at or around the electrical connection point(s) between the metal layers: (iv) the physical joining of the metal layers to create an electrical connection point between the metal layers may be performed by means of laser welding, riveting or soldering; (v) a recess or pouch in a metal layer or in both metal layers may be formed to house the RFID chip module or flexible circuit; (vi) the metal card body may be disposed with a slot to accept a lanyard while at the same time the aperture in the metal card body enhances the RF performance of the RFID chip module; and (vii) the slot or aperture passing through the entirety of the metal card body may be further disposed with a slit extending inward to an area around the electrical connection point(s). A variation in the construction of the proximity card, contactless smartcard or dual interface smartcard may support a slit extending from a perimeter edge on each metal layer to the lanyard slot to further enhance RF performance.
The gap created between the sandwich of two metal layers 420A and 420B represents the RFID slit technology, a replacement for a physical slit passing or cutting through the entirety of each metal layer. One further step is required to the card configuration in order for the card to act as a coupling frame.
The diagram shows a first metal layer (ML-1) 520A having a slot 530A in the metal layer. The second metal layer 520B has an aperture 530B. The connection point or points of one metal layer (ML-1) may be connected with the opposing connection point or points of the other metal layer (ML-2), in various combinations. The metal region or position to each side on two overlapping metal layers may be denoted by the letters A and B. The connection may be any form of electrical connection including soldering, through-hole plating, conductive adhesive, crimping, welding, riveting, etc. The electrical connection renders the metal layers to act as coupling frames. The joining or electrical connection is represented by 580.
Folding a Single Metal Layer to Make a Card Body with Two Metal Layers
Card bodies with two (or more) metal layers, each having a slit and functioning as a coupling frame are known. See, for example, US 20160110639, which describes stacked and overlapping coupling frames, wherein for example (text abridged): S66
Commonly-owned, copending U.S. Ser. No. 16/991,136 discloses, at FIGS. 12, 13, 14, therein, that a single metal layer may be folded over itself what will become a front layer and rear metal layer, each having a slit (S) and module opening (MO) to act as a coupling frame (CF), and the metal frame (MF) being supported by struts (SRTs) connected to said metal frame (MF) as part of the metal inlay (MI), according to the invention. Foe example:
In the constructions disclosed immediately hereinabove, each metal layer, or each portion of a “double-wide” metal layer may be formed, ab initio, with a slit, so that the resulting metal layer will be able to function as a coupling frame. Most coupling frames will also have module openings, which may also be art of the initial processing of the metal layer, or portion of a double-wide metal layer.
The following
In the above-described manner, a single sheet of metal may be folded upon itself (with an insulating layer, such as adhesive therebetween) to form a two metal layer construction for a card body (CB) of an RFID device such as a proximity card (PC) or a smartcard (SC). Notice that only one of the layers (formed by the two side portions) will have a slit, which is well supported by the other layer (formed by the middle portion). Optionally, a slit may also be formed in the middle portion, and should be offset from the slit formed by the two folded-over side portions.
Although the slit or gap is continuous as a result of the folded metal edges meeting in the center of the card body, it is feasible to electrically connect both folds at a point along the continuous slit or gap to concentrate surface currents.
The slit S 730 and the gap G 790 represent metal edges in which surface current flow.
The gap G at the perimeter edge of the card body is not visible in this perspective view.
Note that both of the outer winding OW and inner winding IW are enlarged to form the coupler coil CC and substantially fully encircle the antenna module AM in the coupling area (144). The free ends (a, f) of the card antenna CA are shown disposed at the right edge of the card body CB.
The extension antenna EA has one end extending from an end of the coupler coil CC, and another end extending from an end of the card antenna CA, and exhibits a cross-over. The extension antenna EA (or extension coil, or extension loop) is disposed so as to have a portion adjacent two sides (or approximately 180°) of the coupler coil CC.
An antenna extension EA component is shown as an “extension” of the inner winding IW, comprising some turns of wire in a spiral pattern disposed near the antenna module AM in the left hand side of the top (as viewed) portion (120a) of the card body CB. The extension antenna EA may be disposed outside of, but near the coupling area (144) of the card body CB, in the residual area (148).
In this example, the coupler coil CC component of the booster antenna BA does not need to be a “true” coil, it does not need to have a cross-over. Rather, it may be a horseshoe-shaped “open” loop which substantially fully, but less than 360°, encircles the coupling area (144) for inductive coupling with the module antenna MA of the antenna module AM.
In this example, the card antenna CA is a true coil, in the form of a spiral extending around the peripheral area (142) of the card body CB, and exhibits a cross-over.
The extension antenna (or extension coil) EA has two ends—one end is connected to the coupler coil CC, the other end is connected to the card antenna CA. The extension antenna EA may be formed as a spiral of wire embedded in the card body CB, contiguous with one or more of the card antenna CA and coupler coil CC, and is a true coil which exhibits a cross-over, and contributes to the inductive coupling of the booster antenna BA. The extension antenna EA may be disposed in the residual area (148) of the card body CB, and is shown as being disposed only in the upper half (120a) of the card body CB, but it may extend to the lower half (120b) of the card body CB, including any or all of adjacent to, above, below or into the embossing area (146).
The extension antenna EA (or extension coil, or extension loop) has one end extending from an end of the coupler coil CC, and another end extending from an end of the card antenna CA, and exhibits a cross-over. The extension antenna EA is disposed so as to have a portion adjacent two sides (or approximately 180°) of the coupler coil CC.
In this example, the layout of the inner windings (IW) and outer windings (OW) of the card antenna CA are slightly different than in
In this example, the extension coil EA is a true coil having a cross-over, is disposed in the residual area (148) of the card body CB, and is shown as being disposed only in the upper half (120a) of the card body CB, but it may extend to the lower half (120b) of the card body CB and into the embossing area (146). In this example, the extension antenna (EA) may occupy a larger area and have a narrower pitch (closer spacing of windings) than the extension antenna EA of
A benefit of having the extension antenna EA in a booster antenna BA may be to increase the inductivity of the booster antenna BA while reducing its resonance frequency. For example, without the extension antenna EA, the card antenna CA may require significantly more windings (such as in excess of 15 windings, instead of only 7 or 8 windings), depending on the spacing between the windings and the diameter or cross sectional area of the conductor of the wire used to form the booster antenna BA. It is within the scope of the invention that the card antenna CA has only one winding.
The booster antennas (BA) of
Card with Coupling Frame Antenna
US 2018/0341847 discloses SMARTCARD WITH COUPLING FRAME ANTENNA, and describes a smartcard (SC) having a card body (CB) and a conductive coupling frame antenna (CFA) extending as a closed loop circuit around a periphery of the card body, and also extending inwardly so that two portions of the coupling frame antenna are closely adjacent each other, with a gap therebetween.
The shape of the coupling frame antenna, as it extends inwardly from the left (as viewed) side of the card body to the module opening area, results in two side-by-side portions of the coupling frame antenna (CFA) being closely adjacent each other, with a gap therebetween. This gap may be comparable to the slit (S) in a conventional coupling frame (CF)
Generally, a “coupling frame” (CF) may comprise a metal layer, metal frame, metal plate or any electrically-conductive medium or surface with an electrical discontinuity such as in the form of a slit (S) or a non-conductive stripe extending from an outer edge of the layer to an inner position thereof, the coupling frame (CF) capable of being oriented so that the slit (S) overlaps (crosses-over) the module antenna (MA) of the transponder chip module (TCM), such as on at least one side thereof. The slit (S) may be straight, and may have a width and a length. In some embodiments, the slit (S) may extend to an opening (MO) for accepting the transponder chip module. In other embodiments, there may only be a slit, and no opening for the transponder chip module (TCM). Coupling frames of this type, typically a layer of metal with an opening for receiving a transponder chip module, and a slit extending from a periphery of the layer to the opening, wherein the slit overlaps at least a portion of the module antenna, may be found in U.S. Pat. Nos. 9,812,782, 9,390,364, 9,634,391, 9,798,968, and 9,475,086.
In contrast thereto, the coupling frame antenna (CFA) of the present invention may comprise a continuous conductive path or a track of wire or foil formed around the transponder chip module (TCM), such as by embedding wire or by etching a conductive path or track in the form of a one turn (or single-loop) antenna. The coupling frame may be planar or three dimensional (such as a curved surface). The coupling frame for inductive coupling with a reader may couple with either a passive or an active transponder chip module.
The path (or track) of the single-loop coupling frame antenna (CFA) may generally be around the periphery of the card body, but may extend to an inner position of the card body and double back on itself at selected areas of the card body, leaving a gap or void between the adjacent portions of the track. The space (void, gap) between closely-adjacent portions of the single-loop coupling frame may perform the function of a slit (S) in a conventional coupling frame—namely, overlap a portion of a module antenna in the transponder chip module—but it is distinctly different in construction. The coupling frame antenna (CFA) may wrap around the position (or module opening MO) for the transponder chip module (TCM).
Generally, the term “slit” will be applied to coupling frames (CF), and the term “space” will be applied to the corresponding feature of coupling frame antennas (CFA). However, in some instances, the term “slit” may be used to describe the space (void, gap) between closely-adjacent portions of the single-loop coupling frame antenna (CFA).
The overlap of the slit (or space) of either a coupling frame (CF) or a coupling frame antenna (CFA) with the module antenna (MA) may be less than 100%. In addition, the width and length of the slit (or space) can significantly affect the resonance frequency of the system and may be used as a tuning mechanism. As the width of slit (or space) changes, there is a resulting change in the overlap of the slit with the antenna.
Another distinction is important. When referring to a conventional overall coupling frame (CF) as being “continuous”, it should be understood that the slit (S) represents both a mechanical and an electrical discontinuity in an otherwise continuous (electrically and mechanically) structure. The slit is a feature extending from an edge of the coupling frame (CF) to an interior position thereof (typically, the module opening for the transponder chip module).
Some embodiments of smartcards having coupling frames and booster antennas will now be described.
A smartcard (SC) has a metal card body (MCB) with an opening (MO) for a transponder chip module (TCM) and a slit (S). The metal card body may function as a coupling frame (CF). See, e.g., U.S. Pat. Nos. 9,475,086, 9,798,968.
Regarding the slit . . .
A booster antenna (BA) is provided, and may comprise of a wire embedded antenna ultrasonically scribed into a plastic layer (PL). The booster antenna may have three portions, or components:
The booster antenna may form a closed loop, and may have no free ends.
The sense coil (acting like a pick-up coil) interacts/couples with the coupling frame, at the location of the slit, and may be configured with different patterns, as follows:
Ferrite may be disposed between the plastic layer and coupling frame, but may be disposed only within (an interior area of) the booster antenna, such as on the plastic layer (PL) in areas not occupied by the booster antenna. This may be referred to as ferrite disposed between the booster antenna and the coupling frame.
Booster Antenna Coupling with RFID Slit Technology
Contactless cards operating in contactless mode including dual interface (contact and contactless) smartcards may have a coupling frame (CF) and a booster antenna (BA) arranged in a metal card body (MCB) to interact with each other to allow for enhanced contactless communication.
For the purpose of clarity, the sense coil (SeC) may overlap or overlie a slit in a metal layer (ML) or metal card body (MCB), but equally the sense coil (SeC) may be integrated or positioned within the slit collecting surface currents from within the slit and or at the metal edges.
In the drawings, the direction of the windings or turns of the sense coil (SeC) across the slit (S) is portrayed in a perpendicular and parallel manner, but as discussed above, the direction and shape of the coil (SeC) may be a combination of perpendicular and parallel windings, to optimize the self-inductance and minimize the negative mutual inductance which results in current cancellations. Further, the sense coil (SeC) can meander around or within the area of the slit or slits. The sense coil (SeC) may be part of a wire embedded booster antenna (BA) or the sense coil (SeC) may be on a flexible circuit assembled to the metal card body. An anti-shielding material such as ferrite, not shown, may be incorporated in the card construction. An air gap may exist between the metal layer (ML) acting as coupling frame and the booster antenna (BA).
In all the schematics presented in which the coupler coil (CC) of the booster antenna (BA) inductively couples with the module antenna (MA) of the transponder chip module (TCM) while the other component elements of the booster antenna (BA) in the particular the perimeter coil (PC) and the sense coil (SeC) harvest energy by picking up surface currents around the area of the slit and the metal card body (MCB), it is feasible to eliminate the coupler coil (CC) and make a direct connection from the perimeter coil (PC) to the RFID chip assembled to the chip module (CM), eliminating also the need for a module antenna (MA) on the face-down side of the chip module (CM). This complicates the manufacturing process as the wire ends of the perimeter coil (PC) would have to be physically connected to the chip module (CM), but it represents a viable alternative which could be cost effective.
In addition, an extension antenna (EA) may be used to tune the booster antenna or potentially drive an electronic component.
Typically, cards may be manufactured (laid up and laminated) in sheet form, each sheet having a plurality of cards, such as in a 5×5 array, and CNC (computer numerical control) machining may be used to singulate (separate) the finished cards from the sheet. Resulting burrs, particularly in the metal layers, may cause defects, such as electrical shorting of the slit. Hence, CNC machining of metal core, metal face or solid metal smartcards may be performed using cryogenic milling, such as in an environment of frozen carbon dioxide or liquid nitrogen.
Some of the card embodiments disclosed herein may have two metal layers, separated by a dielectric coating or an insulating layer, rather than a single metal layer. The two metal layers may comprise different materials and may have different thicknesses than one another. For example, one of the metal layer may be stainless steel while the other metal layer may be titanium. In this manner, the “drop acoustics” of the metal card body may be improved, in that the card, when dropped or tapped (edgewise) on a hard surface, sounds like a solid metal card (making a ringing or tinkling sound), rather than like a plastic card (making a “thud”).
Generally, in order for the smartcard to be “RFID-enabled” (able to interact “contactlessly”), each of the one or more metal layers should have a slit, or micro-slit. When there are two (or more) metal layers with slits in the stack-up, the slits in the metal layers should be offset from one another.
The smartcards described herein may have the following generic characteristics:
Generally, any dimensions set forth herein are approximate, and materials set forth herein are intended to be exemplary. Conventional abbreviations such as “cm” for centimeter”, “mm” for millimeter, “μm” for micron, and “nm” for nanometer may be used.
The concept of modifying a metal element of an RFID-enabled device such as a smartcard to have a slit (S) to function as a coupling frame (CF) may be applied to other products which may have an antenna module (AM) or transponder chip module (TCM) integrated therewith, such as watches, wearable devices, and the like.
Some of the features of some of the embodiments of RFID-enabled smartcards may be applicable to other RFID-enabled devices, such as smartcards having a different form factor (e.g., size), ID-000 (“mini-SIM” format of subscriber identity modules), keyfobs, payment objects, and non-secure NFC/RFID devices in any form factor
The RFID-enabled cards (and other devices) disclosed herein may be passive devices, not having a battery and harvesting power from an external contactless reader (ISO 14443). However, some of the teachings presented herein may find applicability with cards having self-contained power sources, such as small batteries (lithium-ion batteries with high areal capacity electrodes) or supercapacitors.
The transponder chip modules (TCM) disclosed herein may be contactless only, or dual-interface (contact and contactless) modules.
In their various embodiments, the invention(s) described herein may relate to payment smartcards (metal, plastic or a combination thereof), electronic credentials, identity cards, loyalty cards, access control cards, and the like.
While the invention(s) may have been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention(s), but rather as examples of some of the embodiments of the invention(s). Those skilled in the art may envision other possible variations, modifications, and implementations that are also within the scope of the invention(s), and claims, based on the disclosure(s) set forth herein.
Priority (filing date benefit) is claimed from the following, incorporated by reference herein: This application is a continuation-in-part of U.S. Ser. No. 16/991,136 filed 12 Aug. 2020 This application is: a nonprovisional of 63/053,559 filed 17 Jul. 2020a nonprovisional of 63/040,544 filed 18 Jun. 2020a nonprovisional of 63/040,033 filed 17 Jun. 2020a nonprovisional of 63/035,670 filed 5 Jun. 2020a nonprovisional of 63/034,965 filed 4 Jun. 2020a nonprovisional of 63/031,571 filed 29 May 2020a nonprovisional of 63/014,142 filed 23 Apr. 2020a nonprovisional of 62/986,612 filed 6 Mar. 2020a nonprovisional of 62/981,040 filed 25 Feb. 2020a nonprovisional of 62/979,422 filed 21 Feb. 2020a nonprovisional of 62/978,826 filed 20 Feb. 2020a nonprovisional of 62/971,927 filed 8 Feb. 2020a nonprovisional of 62/969,034 filed 1 Feb. 2020a nonprovisional of 62/960,178 filed 13 Jan. 2020a nonprovisional of 62/936,519 filed 17 Nov. 2019a nonprovisional of 62/912,701 filed 9 Oct. 2019a nonprovisional of 62/894,976 filed 3 Sep. 2019a nonprovisional of 62/891,433 filed 26 Aug. 2019a nonprovisional of 62/891,308 filed 24 Aug. 2019a nonprovisional of 62/889,555 filed 20 Aug. 2019a nonprovisional of 62/889,055 filed 20 Aug. 2019a nonprovisional of 62/888,539 filed 18 Aug. 2019
| Number | Date | Country | |
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| 63053559 | Jul 2020 | US | |
| 63040544 | Jun 2020 | US | |
| 63040033 | Jun 2020 | US | |
| 63035670 | Jun 2020 | US | |
| 63034965 | Jun 2020 | US | |
| 63031571 | May 2020 | US | |
| 63014142 | Apr 2020 | US | |
| 62986612 | Mar 2020 | US | |
| 62981040 | Feb 2020 | US | |
| 62979422 | Feb 2020 | US | |
| 62978826 | Feb 2020 | US | |
| 62971927 | Feb 2020 | US | |
| 62969034 | Feb 2020 | US | |
| 62960178 | Jan 2020 | US | |
| 62936519 | Nov 2019 | US | |
| 62912701 | Oct 2019 | US | |
| 62894976 | Sep 2019 | US | |
| 62891433 | Aug 2019 | US | |
| 62891308 | Aug 2019 | US | |
| 62889555 | Aug 2019 | US | |
| 62889055 | Aug 2019 | US | |
| 62888539 | Aug 2019 | US |
| Number | Date | Country | |
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| Parent | 16991136 | Aug 2020 | US |
| Child | 16995849 | US |
